<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>

        .a{
            width: 500px;
            height: 500px;
      
            text-align: center;
            margin: 0 auto;
        }
    </style>
</head>
<body>
    <div class="a">
     <form action="">
         用户名:<input type="text"><br>
         &nbsp;&nbsp;&nbsp;密码:<input type="password"><br>
         <input type="button" value="登录">
         <input type="reset" value="重写">
     </form>
    </div>
</body>
</html>